1. Field of the Invention
The present invention relates to a method and apparatus for dispensing fluids, particularly fuel, with multiple product choices, through a single product selector valve, a single meter, a bypass loop and single or multiple product outlets. It is the purpose of the multi-product dispenser to reduce the number of parts, leakage points, and production costs necessary for operating a dispensing system as well as to obtain a higher grade of fluid for the user.
2. Description of the Related Art
Dispensing systems for delivering multiple grades of fluid products are known.
Some systems include multiple-grade fluid sources with single or multiple fluid outlets for dispensing various grades of fluid. Each fluid source includes a pump to dispense the fluid from its source to its respective meter for measuring the volume of fluid. The fluid then remains in its original concentration or it is blended with other fluids to form a separate concentration before reaching the fluid outlet. The problem with these systems is that multiple meters are used to meter the fuel from its respective source. This can increase the costs of manufacturing, increase the volume of the dispensing unit, complicate service, and create more leakage points.
Another problem with these systems occur when a single fluid outlet or fluid line dispenses multiple grades of fluid. Lower grades of fluid can remain in the system while the user attempts to obtain a higher grade of fluid. This contamination can often present a lower grade of fluid than required. One solution is to leave the lower grade of fluid in the system and combine it with higher grade, hoping that the combination would have sufficient grade to satisfy state and federal regulations. However, this can be disadvantageous for users who only dispense a small volume of fluid since the volume within the system creates a large variation on the grade of the fluid and places a design limitation on the system due to the small volume. Another solution is to place residual high grade fluid in the system in order to compensate for the lower grade fluid previously dispensed. However, this can complicate the system and fail to give the user the expected grade of fluid when the highest grade has been selected or a small volume is desired.
Other systems that use only a single meter require multiple control valves in order to meter multiple fluid sources before reaching the fluid outlet. Each fluid source includes a pump to dispense the fluid from its source to its respective inlet selector valve. Only a single inlet selector valve is opened so that the fluid can be measured by the single meter. The fluid then flows from the meter to either a single fluid outlet or through an outlet control valve which dispenses the fluid to its respective outlet when multiple outlets are used. The problem with this system is that the lower grade of fluid may be trapped between each inlet selector valve and the single outlet or each outlet control valve if multiple outlets are used, which can produce a lower grade of fluid than desired. One solution is to decrease the internal volume between the inlet selector valve and the single outlet or each outlet control valve when multiple outlets are used. However, this can be disadvantageous for users who only dispense a small volume of fluid since the volume within the system creates a large variation on the grade of the fluid and it places a design limitation on the system due to the small volume. Another problem with this system is that the multiple control valves can complicate the design of the system, complicate servicing, and create more potential leakage points which are exposed during assembly and servicing of the system which can be limited by state and federal regulations.